Mr. Foo, a mandarin of the lost Empire, in his underground abode at Washington, D.C., prays to the Buddha that the newborn Chinese Republic be overthrown and the Empire restored. Florence, the young daughter of a man high in official circles at Washington, has a hobby for settlement work, and she is seen constantly in the Chinese quarter at Washington. Mr. Foo meets her there, and secretly in love with her, invites her to his place under the pretext of teaching her something of his country, because she has been so zealous in teaching the Chinese of America. She goes to his dwelling the next day, and Mr. Foo gives her a necklace, which he tells her was given him by the Empress of China herself. Florence leaves, and upon returning home, tells her parents of her experience. They are unable to translate the inscription on the necklace, and invite Tu Sing, the Chinese Ambassador, to dinner, with the hope that he will translate it for them. He tells them that the owner of the necklace is a great soldier of the old Empire, but a traitor to the Republic. Rather than create the impression that they are in league with Mr. Foo, Florence and her parents give the necklace to Tu Sing. The ambassador employs a spy to locate Mr. Foo and his followers, who are kindling a rebellion which they intend to fan into a blaze in their own country. The spy gets into the secret underground abode, and after he has reported to Tu Sing, the latter goes to Foo's place and tells the traitor that he can either return to his own country and die as a traitor or take poison where he is. Mr. Foo calmly sits down and drinks the tea containing the poison.